<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://cdn.jsdelivr.net/npm/vue@2.6.14/dist/vue.js"></script>
</head>
<body>
    <div id="root">
        姓：<input type="text" v-model="firstName"><br/><br/>
        名：<input type="text" v-model="lastName"><br/><br/>
        姓名：<span>{{fullName}}</span>
    </div>
    <script>
        const vm = new Vue({
            el:"#root",
            data:{
                firstName:'张',
                lastName:'三'
            },
            computed:{
                fullName:{
                    //get作用？当有人读取fullName时，get就会被调用，且返回的值作为fullName的值
                    //声明时候调用？1、初次读取fullName时，2、所依赖数据发生变化时
                    get(){
                        console.log(1);
                        return "dai"
                    },
                    //当fullName被修改时调用
                    set(value){
                        console.log('set',value);
                        const arr = value.split('-')
                        this.firstName = arr[0]
                        this.lastName = arr[1];
                    }
                    
                }
            }
        })
    </script>

</body>
</html>